The present invention relates to a data storage and retrieval system for retrieving data distributed and stored on a network and presenting the retrieved data by a user-desired presentation form.
This application is based on Japanese Patent Application No. 9-289770, filed Oct. 22, 1997 and Japanese Patent Application No. 9-307460, filed Nov. 10, 1997, the contents of which are incorporated herein by reference.
Generally, data is based on a personal intention and interpretation. Because of the personal preference, data to be provided is constructed from the viewpoint based on the data provider. The provider constructs data to maximize the utility function of the provider and provides the data. A user to which the data is provided also has a utility function and a demand for referring to and processing the data to maximize the utility function of the user.
The architecture of a recent database system is modeled as a three-layer schema. An external schema layer is closest to the application layer of the three-layer schema. This layer provides a specific method (view or presentation form) of viewing a data structure as part of a database to a specific user (or group). Such a database system places prominence to prevent a physical or logical change in the data structure from influencing on the application software rather than to reconstruct the retrieved data in accordance with the viewpoint of the user.
In the conventional framework of database, an end user is not allowed to freely manipulate the view for the database, and no mechanism is available to allow a plurality of users to share view for the database. That is, only viewing based on the database developer/manager is pre sent. The view is associated with not data expression or data behavior but the data structure. As described above, with the conventional view for the database, the data can hardly be reconstructed in accordance with the viewpoint of the user in the true sense.
It is an object of the present invention to provide a data storage and retrieval system which allows a user to freely change the data presentation form from his/her viewpoint to widen the data utilization and promotes data utilization, and a recording medium recording a computer program for data storage and retrieval.
According t o an aspect of the present invention, there is provided a data storage and retrieval system comprising storage means for storing data belonging to a predetermined category and definition data which is made to correspond to the data in advance and describes definitions of a data structure and presentation form, retrieval means for retrieving the data and the definition data made to correspond to the data in advance from the storage means on the basis of input retrieval data, rewrite means for rewriting, based on another definition data stored in the storage means, the definition data made to correspond in advance to data retrieved by the retrieval means and presentation means for presenting, based on the definition data rewritten by the rewrite means, the data retrieved by the retrieval means.
This arrangement allows not only to simply retrieve and present a data space but also to easily display the data in a display form desired by a user by rewriting the definition data of the retrieved data using another definition data.
According to another aspect of the present invention, there is provided a data storage and retrieval system comprising storage means for storing data belonging to a predetermined category and definition data describing definitions of a structure and presentation form of the data, retrieval means for retrieving presentable data from the storage means on the basis of designated definition data, and presentation means for presenting, based on the designated definition data, the data retrieved by the retrieval means.
This arrangement allows not only to simply retrieve and present a data space but also to retrieve and present data matching a presentation form desired by a user.
Additional objects, and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention.
The objects and advantages of the present invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.